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    <title>Document</title>
</head>

<body>
    <select id="sel">
        <option value="liangban">凉拌黄瓜</option>
        <option value="">黄瓜皮蛋</option>
        <option value="">黄瓜皮蛋</option>
        <option value="">炖黄瓜</option>
        <option value="">油炸黄瓜皮</option>
    </select>
    <script>
        console.log(sel.selectedIndex);
    </script>
</body>

</html>